Drafting equipment



Nov. 23, 1948. E. E. HuRsT x-:TAL 2,454,383

' DRAFTING VEQUIPMENT Filed Aug. 20, 1945 5 Sheets-Sheet 1 N0. 23, 1948-E. E. HuRsT ETAL 2,454,388

DRAFTING EQUIPMENT l Filed Aug. 2o, 1945 s sheets-snaai 2 ,EJ 7 6,0 3f60 59 ze) y I .sa 22 .n .a7

NOV. 23, 1948. E, E, HURST Ell-AL I 2,454,388

DRAFTING EQUIPMENT Nov. 23, 1948. E. E. HuRsj' ETAL 2,454,388

DRAFTING EQUIPMENT Fild Aug. 2o, 1945 5 sheets-sheet 4 @p05 /BQ l.. I lu.. .n 2g 45 l 46 'du' 25 A ze l 27 v1| mmmi 63 l 65 62 62 M j Y Y J23i@ 'u r +34 TT I, y +16 l' T39 .a3 v f, sa

Nav. 2 3, 1948. E E, YMURST TAL 2,454,388

DRAFTI'NG EQUIPMENT Filed Aug. 2o, 1945 'TMI L@ 5 Sheets-Sheet 5 a e 24I 64` g o 32 l o 4 gli-'.54

@5 MGM/Mm Patented Nov. 23, 1948 `UNITED STATES PATENT yOFFICE.

DRAFTING EQUIPMENT Edmund E. Hurst and John Warren Paxton, Bloomington,Ill., assignors of one-third to Francis Lee Go, Bloomington, Ill.

Application August 20, 1945, Serial No. 611,516

12 Claims.

.. in connection with the conventional drafting board; to provide animproved construction and relative arrangement of straight edges forrespectively determining the vertical and the oppositely-convergingdiagonal lines of a perspective View; to provide improved means formounting said straight edges for horizontal shifting on the normallyvertically movable drafting board straight edge and connecting saiddiagonal straight edges to Vanishing points whereby the diagonalstraight edges always assume the proper relationship to each other andto the vertical straight edge so as to correctly represent theperspective angles as the said straight edges are shifted on thedrafting board; to provide improved means for extending the vanishingpoint connections beyond the normal boundary of the drafting board; andto provide improved means for retaining said diagonal straight `edges inposition against incidental shifting during the drawing of lines.

Preferred forms of perspective drafting equipment, constructed inaccordance with this invention, are shown in the accompanying drawings,in which Fig. l is a plan view of one form of perspective draftingequipmentapplied to a conventional type of drafting board;

Fig. 2 is a side elevation of the same;

Fig. 3 is a cross-sectional viewtaken on the line 3-3 of Fig. 1;

Fig. 4 is a similar view taken'on the line 4-4 of Fig. l;

Fig. 5 is a reverse View of the arrangement shown in Fig. 1;

Fig. 6 is a `view similarto Fig. 1 but showing the use of auxiliary armsby which the Vanishing `point means are extended beyond the border ofthe normal drawing board;

Fig. 7 is an enlarged, fragmentary, cross-sectional view taken on theVline 'f-l of Fig. 6;

Fig. 8 is a similar view on the line 8-8 of Fig. 6;

Fig. 9 is a transverse sectional View taken on the line 9-9 of Fig. 8;

Fig. 10 is a perspective of one end of one of the diagonal straightedges, showing the formation of the pin to which is attached one end ofthe flexible connection which co-acts with the vanishing point means forcontrolling the positions of the diagonal straight edges;

Fig. l1 is a plan View similar to Fig. 1 but showing a modifiedpivotalmounting of the diagonal straight edges and a modification ofvanishing-point means and the connection of the diagonal straight edgesthereto;

Fig. 12 is an enlarged, fragmentary, cross-sec-y Fig. 13 is an enlarged,fragmentary, cross-sectional view taken on the line I 3-I3 of Fig. 11;Fig. 14 is an enlarged, fragmentary, reverse View of the pivotalarrangement of the diagonal straight edges employed in the embodimentrshown in Fig. 11;

Fig. 15 is a View similar to Fig. l but showing an addition of means forretaining the diagonal straight edges `in temporary xed position duringthe drawing of lines;

Fig. 16 is an enlarged, fragmentary, cross-sectional View taken on theline` lli-I6 of Fig. 15;

Fig. 17 is a View similar to Fig. 16 but showing the retaining meansdepressed;

Fig. 18 `is an enlarged, cross-sectionalV View taken on the line I8-l8of Fig. 16;

Fig. 19 shows a further modification inthe retaining means by which thediagonal straight edges may be temporarily held in place during theruling of lines;

Fig. 20 is an enlarged plan `view of said retaining means;

Fig. 21 is a reverse view of the parts shown in Fig. 20; and

Fig. 22 is a cross-sectionalview taken on the line 22-22 of Fig. 20.

Perspective drafting equipment, constructed in accordance with any ofthe preferred embodiments herein shown, is designed for use with sadrafting board 23 and comprises a plate 24 on which is arranged thestraight edges 25, 26, and 21, the two latter of which have their endsconnected to vanishing-point means 28 and 29 through the medium of a`flexible connectionl 3D and which may be firmly retained againstincidental displacement, during the drawing of lines, by means ofsuitable retaining means 3|.

The drafting board 23 may be of any conventional construction, usingwood or plastic,

equipped with a horizontally-disposed straight edge 32 movablevertically on the board and provided with clamping means 33 wherebydrawing paper is secured in proper position on the board.

The drawing board 23, with which the several embodiments of thisperspective equipment have been combined, is of plastic construction.The straight edge 32 has clips 34 fixed at the ends thereof which extendover the lateral edges of the board. These clips are secured to a cable35 (see Figs. 4 and 5) which passes around rollers 36, located at thecorners of the board 23 on the back thereof, and which is crossed asindicated in Fig. 5. Such a cable connection ensures the straight edge32 being held perfectly normal to its vertical duringmovement on theboard.

The board 23 being of vplastic material, it is necessary to provide someother means than thumb tacks for holding the paper 31 in place, To thatend there is provided the clamping means 33 in the form of a bar 38which is heldui in 'place by means of a pair of spring clips 39.

The plate 24 of the perspective equipment liken wise is preferably ofsome plastic material. exact form of this plate may be varied dependingupon how the straight edges 25,l 2li,A and21 are to be mounted thereonand connected to thevan.-

ishing-point means 28 and 29. Regardless of the form of the plate 24 tolaccommodate the arn rangement of the straight edges 25, 26,-and211 andthe vanishing-point attachments, such a plate is provided with' a pairof bars 40-and 4I' relatively adjustable on .the plate so that the platemay be slidably clamped in viixed normal relation-H The shipto straightedges 32 of varying. widths. .To

that end, the bar 49 is grooved at 42 (seeFig. 3)

to nt under the rear or lower edge of the straight. edge` 32., Thebarili is supported on the plate,24 by means of threaded pins 43extendingthrough.

slots. .so..that the .bar Mmcan beiproperlyposiftionedagainst the. otheredge of the straight. edge 32..`

The vertical straight edge. .may lbe integral With the ,plate .24, asshown. in. several of-the em.- bodiments, or it may be .separatelyformed and rigidlyattached, as showninFigs. 1920, and.21.

In any event, it is positioned. sothat it is perpenthere has beenprovided a pair of auxiliary rollers 45 and 46 mounted on the outer endsof arms 49 and 50, respectively. These arms are formed with slots 5|"and 52 through which extend pivot pins 53 and 54, respectively, wherebysaid arms 49`and 5D are pivotally supported on the back of ther.\.board:..23. The arms 49 and 5D may be clamped in extendedpositions asshown in Fig. 6, or...in'retracted 'positions as shown in Fig. 5, bymeans .of the. winged thumb-nuts 54 and 55 mounted on the pivot pins 53and 54.

The alinement of the straight edges 26 and 21 with .the vanishing pointsis effected by means of a flexible 'connection 30. Preferably this is inthe form ofa coiled wire spring which,.in the eme bodiment shown inFigs.' 1 t-o 8,'ha`s the ends lcon'- nected to the straight edges 26"and2l. so that'H the intermediate `Ipart'thereof forms a loop which.extends around the rollers 45 and`45`-.or 45' land In the embodimentshown in Figs; ll'to 21,". the flexible connection 3.has itsendsconnected. tothe clips,41 and 48"and the intermediate part` thereofformsa loop which extends arounda sin.

straight edges, being designed to guidethe .drawing .-.of,the,.oppositelyfconverging A.diagonals ofa perspective, of necessitymustalwaysbe alined withthe respective vanishing points of aperspective, regardless ofthe positionof the plate 24 on thefstraight... edge.. 32.. .-or. the. position, .of thevv straighty edge.32.;vertically .on the-board. Ac.-

cordingly,` it is.. necessary l.toprovide .a flexible connectionbetweenfthe .outer ends of-.the pair of straightedgeszand 21 andthevanishingfpoint.

means .28.and29.. i.

Generally .the .vanishing-point. means 28 Vand 29, with which4 thestraight. edges 26.and. 21 must.. be constantly alined,..normallywouldbe xed yon the ,board 23.... However, there are occasionswhen it is..desirable .to have. these. Vanishing-point means locatedbeyondtheperimeter of the board 23 'so as tokeepthe straightedgesZB and '21 inproper. relative relationship to.each other and. to the straight edge25'whenjit is necessary to carry the formation of vertical anddiagonallines at the extreme upper portions of the drawingW gle roller56,' 'as in the embodiment shown in. Figs.. 11,'12, and. 14,01 around apair of rollers 56' and 56, as in the embodimentshown in. Figs.. 19to... 22.

In. the embodiment.. shown inFigs. l -to..8.the. diagonal straight edges26.'.and'211have a. pin 51.'. formed. on the. outer,.ends.,thereoftoowhichthe.'` end .of the. spring is secured.

As .an alternative .to providing .aflexible .conf-. nection.v of .thetype` and.. arrangement herein...4 shown, ,cables could. be ,usedextending 1from-the .1 outer ,ends of the diagonal.straight` edgesv25and.-, 21 over rollers suitablymountedonfthe board to represent the.vanishingfpoints 28- and 29:-andw connected toweights.

The straight edges-25, 26,andf21:.are.beve1ed, as clearly-shownintheguresgrso las to facilitate the drawing-of: lines on'the paper-31iny theclosest; i possible proximity to the edges of the respectiveparts.4

Because ofthe flexible connection of I the `1diag-y onal arms y26-and21to .thevanishingrpoint meansF 28 and 29, it is necessary to soarrangethemounting of ythe arms -26 and-21 onthe plate 24 that theymaybe most" conveniently 'held' against-l vincidental displacementduring-thevdravving of.;lines L' along their edges. Thedrawingsillustrate several fways -in which this 'may 'be' effected: fIn. the embodiment shown in Figs. l to .5, this retainingmeansf3lisaprovided: by having'the" shank 58'of a bushing 59 extended throughsuitable openingsf inf eachziof-the 4arms.' :26 rand; 21 and' secured.in fixed relationship to the respective armfby'means ofv a -pin 60. Thefbushingsf59 thus formbearingsqforv the.l pivotal connectioncfxthestraight#v edges-26and21 to the plate 24',` andthelilange;

parts of the bushingsy extend. aboveA -thexplate 24;.y Thus, in.Y thismodificationyyvhenfit is .desiredto temporarily" secure onez, off thestraight-.edges ".26A 12 or 21';againstxdisplacement; whiledrawingv a.li'ne therealong, it is only necessary to press vvithgthe finger of onehandy downy upon f the proper bushing 59, thus pressing the respectivearm .fairlyrmly `against the paper. Thereupon, with rea'- sonablecare,-a line Vmaybe drawn along the straight, edgefwithout causingAanydisalinement of :the straight edge with'its, respective vanishingpoint.

In the embodiment,.shown fin. Figs.l 15 to 16, the retaining5means13lemployswa pair of arms 6 I and 6Zmountedfalong.itheireybase:edges :tothe f base edge of the plate 24 so that; the outer ends of the arms aredisposed above the bushings'SB which are fixed to the straight edges 26and 21. A Washer 63 of friction material is located on the under facesof the outer ends of the arms 6I and 62 concentrically of the bushings58 so that when the outer ends of said arms are depressed to bring thefriction Washers 63 into engagement with the transverse flange of thebushings 58,l the straight edges 26 and 21 are held against incidentaldisplacement.

'In the modification of the retaining means shown in Figs. 19 to 22,discs 64 and 65 are se'- cured, by means of pins 66, to brackets 61which in turn support the straight edges 26 and 21. Intermediate thesediscs 64 and 65 are pivotally mounted -a pair of friction blocks 68 and69. These are movable into and out of friction-a1 clamping engagementwith the respective discs 64 and 65 by means of arms 10 and 1|, pivotedat 12 and 13 and having tongues 14 and 15 engaged in suitable recessesin the respective brake shoes 68 and 69. A spring 16 mounted on a nob11, xed to the plate 24, contacts the a-rms 1U and 1| and normallyshifts them so as to retract the respective friction blocks 66 and 69. l

For the modification shown in Figs. 1l to 14, the temporary retention ofthe straight edges 26 `and -21 against incidental displacement iseffected simply by pressing that portion of the straight edge 26,contiguous With the pivot pin 66, against the concentric portion ofthestraigh edge 21 and against the plate 2-4.

The operation of this equipment is thought to be more or less obviousf-rom the foregoing description and,.therefore, not to require detailedyexplanation. y Once the station point for a particular per'- spectiveview has been determined, the lplate 24 is placed in position so as todraw the main central vertical line along the vertical straight, edge25.'`

On this the upper and lower points yfrom which the diagonals diverge tothe vanishing points are determined. Thereupon the plate 24, when shift:ed relative to the straight edge 32 and the straight edge 32 is shiftedon the board 23, will bring first one and then the other of the straightedges 26 and 21 to intersect the vertical line at these critical points.Thereupon the main diagonal lines may be drawn. Subsequently the pointsalong the diagonals at which the two extreme verticals are to be drawnare determined, and the parts moved to bring the vertical straight edge25 in position to permit the drawing of such lines.

Depending upon the nature of the object to be drawn in perspective, theplate 24 is moved back and forth on the straight edge 32, and thestraight edge 32 is moved up and down the board 23 to successively bringone or the other of the straight edges 25, 26, and 21 into properposition to draw the corresponding detail lines of the figure.

In Iall of the shifting of the straight-edges 26 and 21 relative to eachother and to the straight-i edge 32, or in their shifting with thestraightedge 32, the spring 30 is constantly kept in tension but is freeto shift relative either to the vanishing point means 28 and 29 or tothe pivoted ends of the straight-edges 26 and 21.

When the straight edge 25 is once positioned for the drawing of avertical line, it can be readily held against incidental displacement bysimply pressing the plate 24 into contact with the drawing support 23.When one of the diagonal straight edges 26 or 21 is positioned fordrawing 6 a diagonal line, it may be held against incidentaldisplacement by depressing one of the parts of any one ofthe severalmodifications, of the retaining means 3I, which have been hereinbeforedescribed.

Variations and` modifications in the-details of structure andarrangement of the parts may be resorted to Within the spirit andcoverage of the appended claims.

We claim:

, l 14. Drafting equipment of the class described comprising, a supportproviding a drafting surface, means mounted on said support and movas toautomatically effect the variable divergent disposition of saidstraight-edges when said firstmentioned means is moved about saiddrafting surface.

2. Drafting equipment of the class described comprising, a supportproviding a drafting surface, means mounted on saidrsupport and movablein a plane parallel to said drafting surface between opposite edges ofsaid support, a pair of straight-edges pivotally attached to said means,a coiled spring connected to said straight-edges at the ends oppositesaid pivots and forming a loop between said ends, and a pair of meansattachable to said support at spaced points thereon and y position ofsaid straight-edges when said firstmentioned means is moved about saiddrafting surface.

3, Drafting equipmentof the class described comprising, a supportproviding a drafting surface, means mounted on said support and movablein a plane parallel to said drafting surface between opposite edges ofsaid support, a pair of straight-edges pivotally attached to said means,a flexible element connected to said straight edges at the ends oppositesaid pivots and forminga loop between` said ends, and a pair of meansmounted on arms adjustably attached to saidsupport so as to positionsaid pair of means `beyond the normal perimeter of said support andadapted to engage said iiexible element so as to keep the loop thereofin tension between said pair of straight-edge ends but freely shiftablerelative to said pair of attachable means so as to automatically effectthe variable divergent disposition of r said straight-edges when saidfirst-mentioned means is moved about said drafting surface.

fl.` Drafting equipment of the class described comprising, a supportproviding a drafting surface, meansmounted onsaidsupport and movable ina plane parallel to said drafting surface between opposite edges of saidsupport, a member detachably connected to said means, a `pair'ofstraight-edges pivotally attached to said member, a flexible elementconnected to said straight edges at the ends opposite said pivotsand-forming a loop between said ends, and a pair of means assunsea'ttadnabie 'te said simio atfspacejdpomtsthere'- v'on fada'pted t'oengasaidfle'xlibl'e element so 'a'sto'keep thelloop thereof yint'ensionbetween said ipa-irof straight-edgefendsibut'freelysliiitableielative tosaid pair of attachable means-"so as to automatically geffectl thevariable 'divergent dis- Tposition of said Istraightedges Aiii/"hen'said rsttmantiened vliiieans `is moved about said drafting surface. l'I 5. A drafting equipment of the class described comprising a supportproviding a drafting sur- "face,l a horizontal straight-edge mounted for"movement in a plane parallel to said drafting vsurface betweenlopposite edges of said support, 'aA member shiftably mounted`longitudinally of said straight-edge, a pair of `straight-edges pivot-'ally attached to said member, a flexible element vconnected to saidstraight-edges at the ends opposite said pivots vand forming a loopbetween said "ends, and a pair of means attachable at spaced points onsaid support and adapted to engage said jii'exiltile elements so 'as tokeep the loop thereof in tension between said pair" of straight-edgeends but freely shiftable relative to 'said attachable means 'so as toeffect the variable divergent disv"position of said pair ofstraight-edges when said horizontal straight-edge and member are movedabout said drafting surface.

6. Drafting 'equipment of the class described comprising, a supportproviding a 4drafting surface, means mounted on said support and movablein a 'plane parallel to said `drafting surface between opposite edgesofl said support, a member vdetachabl'y connect-ed to said means, a pairof straight-edges pivotally attached to said member,

a iiexibl'e element yconnected to said straightedges at the endsopposite said pivots and form- -ing a loop between said ends, a rpair ofmeans attachable to saidfsupport at spaced points thereon and adapted toengage said flexible element so as to keep the loop thereof in tensionbetween Said pair of straight-edge ends but freely shift- 'able relativeto said pair of attachable means so as to automatically effect thevariable divergent disposition of said straight-edges when 'saidfirstmentioned means is moved about said drafting surface, and othermeans mounted on said membera'nd pressable into contact with saidstraightedges to hold them against accidental movement during thedrawing of a line there'along.

7. Drafting equipment of the class described comprising, a supportproviding a drafting surface, means mounted on said support and movablein a plane parallel to said drafting surface between opposite edges ofsaid support, a pair of straight-edges pivotally attached to said means,other means attachable to said support at spaced points thereon, and aexible element connecting said straight edges with said other means andforming a loop between the ends of said straight- 'edges' and whichelement is kept in tension when said member is moved about said draftingsurface.

`3. Drafting equipment of the class described comprising, a supportproviding a drafting surface, means mounted on said support and movablein a plane parallel to said drafting surface between opposite edges ofsaid support, a pair of straight-edges pivotally attached to said means,other means attachable to said support at spaced lpoints thereon, and a-coiled spring connecting said straight edges with said other means andforming a loop between the ends of `said straightedges" and which springis kept in tension when said. member is moved about said draftingsurface'.

8 9. rafting @quimii-ent or the class described comprising, a`s'upifiort providing a draftingsr'- face, -means mounted'on saidsupportarid'i'riov'able in a plane` paralll 'tad drafting slllflff b"- tweenoppositeed'ges of said support,` a pair of straight-edgesv pivotallyattached to said means, other me'ans'attachable to said support atspaced points thereon, a coiled spring connecting :s'ad straight-'edgeswith said other means arid forrr'ring a loop between the ends o'f saidstraight=dges and whidh spring 'is kept in tensionnwhn 's'aid niemeeryis moved about saiddrafting surfaceya'rid means` and lpressable intocontact with said Astl"aliglfit-edges to hold them against ao'fiidnt'almovement during the drawingof'a line th'erealo'ng. 10,'Draft'in'gequipment of the y'class' described comprising, a support providing adrafting surface, means mounte'djon said support and movable in'a planeparallel to'said Ydrafting surfac'e between opposite ledges of 'saidsupport, a pai-fof 'straightdges pivotally attached to 'said means,other Ieans atta'ohable'to Said' support at yspaced points thereon, acoiled spring connecting straight-edges with said either-means 'andfoiiminga loop-between the ends of said straight-edges and which springis kept in Vterls'ion"when said member is 'moved labout said draftingsurface, said 'other means mounted "on said firstanien'tin'ed meansandv-selel'jtvely press-able into contact with said straight-edges Ytoy'hold each against accidental movement during thedrawin'g' of fa 'line'there'along v l 11. Drafting equipment of the class describedcomprising, a member mountable on a I iean's attached to a draftingsurface support and movable in a plane parallel to said draftingsurface, apair yof straight-edges pivotally attached lto 'said 'ienber,a flexible element connected to' :the ends "of said straight-edges andforming a loop between the'ends thereof afnd adapted for attachment to4a pair of means on' Vsaid support whereby said element `is kept .intens'ion' when said member is 'moved aboutsaid drafting' surface.

' 12; Drafting equipmentof the yclass described comprising, a membermountable on a means 'attached to a'drafti-ng surface support andmovable in' aV planev parallel to said drafting surface, a pair ofstraight-edges pivotally atta-ched'to said member, a flexible elementconnected to the ends 'of sai-dv straight-'edges and forming a loopbetween the `ends thereof and adapted for connection'to means attachableto said support at spaced points whereby said loop is maintained intension between said pair of straight-edge ends but freely shiftablerelative` to said attachment means when said inst-'mentioned means ismoved `about said drafting surface.

EMUND E. HURST. JOHN WARREN PAXTON.

RFRENCES CITED The i following ref "erenc'esI are file of this patent:

UNITED STATES PATENTS of record in the

